Yes and No and Yes. It can be pretty bad-ish... it can be significantly less bad if you're less picky about what dungeon you are queuing for, or queuing for something popular. I'm inclined to DPS queue while making dinner and/or do dailies and/or browse imgur or forums. Pickiness is the bane of your existence when it comes to queues.
There are too many Dragoons, but there's an extreme shortage of good Dragoons. For whatever reason people want to speculate, Dragoons on average play noticeably worse than other DPSers. Good Dragoons are hard to find and in my opinion, highly desirable. That opinion is not a common opinion, but I stand by it anyway.
As someone who has tanked for 12 years, who is just playing a DPS for the first time, I really really really feel this is wrong. Especially in this game, tanks tend to have less mechanics to deal with than DPSers and Healers do, and generally feel like the most forgiving of mistakes of the three roles due to having the most HP and healers prioritizing healing you, even with the incoming boss melee damage. You take avoidable damage as a tank, you'll get healed first; you take avoidable damage as a DPS, better hope the healer finds time for you before the next unavoidable damage comes.
Yeah you gotta use cooldowns for those Mountain Busters and what not, but since most defensive cooldowns have a 12-20 second duration to get it up before you take the hit, you have an absurdly higher margin of error in timing your defensive cooldown.
Threat is a complete and utter non-issue on a single target after the first 10-20 seconds if you have even the most basic levels of competency. PLDs have a bit more difficulty with multi-mobs, as Flash spam isn't very good, but it's still trivial up to 3 mobs with basic tab targeting 101 even if most Duty Roulette Paladins don't seem to be able to handle it.
Tank DPS rotations (for after you've gotten enough threat that you can AFK the rest of the fight) are dirt simple and have no room for improvement or maximizing of damage. But, as I understand it, for most if not all the DPS classes, there is a seemingly endless stream of tricks that allow you to get just 1% more DPS out of yourself. Which might not seem like much, until you start stacking them all together across all 4 DPS in a raid, and then next thing you know between all of ya'll ya'll are doing an extra half a DPSers damage.
This just might be bias of being experienced talking, but I generally have to pay more attention as DPS than as a Tank 90% of the time.
Okay sure there's fights where you have to deal with issues like Spiny Plumes which are tank unique, but I've seen easily 10 times as many wipes due to DPSers taking avoidable damage and/or dying, and/or not putting out enough DPS due to sloppy play, and/or drawing so much healing away from the tank due to taking avoidable damage hits that the tank dies or some bullshit. I notice a great deal of DPSers tend not to realize that they were taking avoidable damage unless they are sitting at low health for a long time; as long as it's healed up in 5-10 seconds, they often never notice they took damage in the first place. Especially in PUGs I'll see people claim stuff like "Well I must've been doing good because I didn't die," when they took tens of thousands of avoidable damage before the group wiped.
DPSing is probably the hardest role in this game, unless the DPSers are playing their role as if it was the easiest role in the game, in which case Healing becomes the hardest role in the game.
Whether healing is harder or easier than DPSing seems to come down almost exclusively to whether or not the DPSers are taking their job seriously.
Ehhhhhh I find melee easier to play than caster even though I've been focusing on caster lately. Whether or not you find melee or caster easier largely depends on how comfortable you are with moving around; I find caster harder because moving comes very naturally to me, and casting tempts me far too often to try and complete that last 0.1s of a cast before moving and occasionally catches me dead, which NEVER happens when I play melee. Also doesn't hurt that melee can attack while moving; they have almost as much ease of mobility as Bards. YMMV. I like to think of Melee as Bards with less range. Just pewpewing away without a care in the world. The fact that an accidental movement won't break my spellcast also tends to make me a bit lighter on my feet as melee, and prone to faster reaction to avoidable damage mechanics. I typically find myself repeatedly tapping my movement button in the direction I need to run when I know an AOE is coming when I'm playing melee, which improves my reaction speed, and I can't do that as caster.
That being said, Tank moving the enemy around sucks, and you have to basically be Dragoon Jesus to actually land your Heavy Thrust under those circumstances. But 90% of the time if the tank is moving around like a hyperactive squirrel on it's 10th cup of coffee made from Mexican jumping coffee beans, if you just politely ask the tank to stand still and explain how mob movement drastically lowers your damage output, they'll stand still for you. And of course for virtually any endgame fight this isn't going to be a problem; it's more a duty roulette dungeon quirk.
IIRC Melee and Ranged have different queues from one another, and melee queues are usually a fair 1/3rd the length of time. It might just be coincidence, but it REALLY feels like it.